Impulse-transmitter.



A. E. KEITH.

IMFULSE TRANSMITTER.

APPLICATION FlLED Dec.24. 1917.

l ,27 9, 352. PatentedSept. 17, 1918.

m: Nukms Fersns cm rnomu-ruo., wAsHnvGmN. n. c.

'UNTTEE sTaTEs TATENT oTTTcE, j

y .ALEXANDER E. KEITH, or IIINSDALE, ILLINOIS, AssIGNoR'To AUTOMATIC ELECTRIC COMPANY, 0E CHICAGO, ILLINoIsAconPoaATIoN 10E ILLINOIS.

IivIPUIxsE-TRAITsI/TITTEIT;

and resident of 'Hinsdale Dupage County, "Illinois,haveinventedcertain new and useful Improvements in Impulse-Transmitters, of which theffollowing is a specification.

My li-n'vei'it'igm relates to an improvement in calling devices orautomati'c or semi-automatictelephone systems, whichA devices are usually located-at the subscribersstations although often at the central station or oper- Y ators position ina semi-automatic system.

The' main objectv of my invention is to 'provide anlim'proved mechanism for operating a'calling device of the above character andwhich not only causes'said mechanism to operate'in a more-eiicient manner butv also materially-increases the life of said device.

It is well known thata deviceof the above character 'is subjected to a very great amount Vof wear Vand tear and that it is of great importance to construct lsaid device in such a manner thatl its`V constant use andthe cooperation of 'its various elements will cause as little frictionalwearing away yas possible. I have discovered that by the use of inhereutly" lubricant material, 'such as raw hide, for example, Iam able toreduce the abrasion of various parts of the mechanism to mil. VOtherdetails and Vfeatures ofimprovement will be more clearly pointed out in the specificationi'ollovs'fingjg` vIn'the drawings, I have illustrated a' callfing device of the type described 'and illustrate'd Vin'zlfwtomoatz'c Telephony byv Smith and Campbell, published in1914. In order to "show the desired improvements, however,

itis to be'understoodthat the features of my invention maybe applied to any well known type of calling device.

Referring' to the' drawings:

Figure 1 is a front viewof a calling 'device v embodying my invention."

Fig. 'Qisa slde view of the same.

Fig. 3 is a rear view of 'the same.

Figs. 4:, 5 and 6' show in detail certain cooperating gears andbearings :which will be 'more fully4 explained 'hereinafter.'I

Y I will lnow' explain: the operation and tail.N Referring toFig."1,`I haveillustrated 4the V front plate of a callingl'f device showing 'aifnger hole dial Il yivoted ata central point i ,5.5 i

aafthtasepiaegei Figs; aim-d 3)" bymeaas 'tooth-10 engages one'o-i:l vthe teeth`7`,"thereby Specification of Letters Patent.' Patented' S8917. 17; 1918. Y i

Application filed December 24,'19127.` Seria1'No.'208,G07. i .Y

of arod and havinga coil spring-3', one end 5 of whichv is fastened to therod orpin 21 :to which'thefingerholeA dial is fastened and, which acts asa pivot `:forl saidv dial, and the onthelunder side of theV base 'plate'Q. This`-1 having gear teeth around' its circumference and havl'ngalso a numberfoi' ratchet-'teeth '7 vcut inthe face of said gearwh-ich'flies adjacentv tothe dial 1. On the rearo-f the is firmly'xed on the dial 1 and whcl'is'cut outf to form a tooth or dog which cooperates withtheteeth 7 on the gear wheelfGLv vThe spring-18is shown more clea-rlyin Fig `6 as being Vfirmly secured vtothe rod '-lf'and" held in'fpos'i't'ion by a pair ofprojections which'it over the lug or stop 9.A Theratc'het tootli'fis indicated by th'eraisedl portion 10, which 'when thedialy is rotated in a'cloekwise direction, rides over" the teeth-7 on` geart'wheel 6 without rotating said'whe'el, however, when the dial is released andreturned to normal by the spring', the ratchet 'uponf ythe pivot rod 4 lisa gear "wheel'f' ldi'al 1in" Fig. 1 is mounted a spring'Sfwhich causing' the gear wheel 6to`rotatje with the"y finger hole dial until the dial reaches nor-v Ymal.v Cooperating with the vgear wheel: 6 i is -'a piniongear 11, which=is firmly mounted on'a pivoted rod 12. The lrod 12 isf'pivo-ted 'at one end in thebridge 13,'which'is formed# out of "a cut out v'pieceof the base'land'at l the other end in va bracket 14, which "is `fastened" tothe rear lof said base plate; The

pinion gear is mounted bn, rthe 4left Vhand end of said'rod, as shown i-n Fig. 5 and has firmlyU secured'thereto a" gear wheel' 15, the'teeth of` which, are cut von 'the bias' to cooperate withlthe 'governor' '16. On the other-.endV the rod'12 is fastened a cam wheelnor'linterrupter"17,which is 4cut away to form tWo arms' or pieces of insulation.v "Thecam' wheel '17"oper`ates iwhen rotated toppen andclose a lcontpict between a suitablefpa-ir ofsprings 18 and 19 to open and close or 'send impulsesf over"k any desired' circuit'which vmaypassy through" said springs.' The'springs18l jaj'ld 19"a`re" mounte'dtogether with the springs f2() and V21 on'abracket 22which is formed out cfa portionof 'the base",A and "arefsep- -with the spring 22, is allowed to make contact with said spring 22, andremain in contact therewith until the dial again reaches normal position. In practice the spring 21 is directly connected to the spring 19 and the operation of the springs 20, 21 and 19 is used for Athe purpose of maintaining the talking equipment of av telephone short cir- `cuited during the transmission of impulses.

VAs previously stated, a governor 16 is associated with the gear 15. This governor controls the speed of rotation of the pinion 11 and therefore of the cam wheel or inter rupter 17 in the following manner: This governor is of well known type and comprises a worm gear which meshes with the gear 15 (Fig. 4L), and a pair of spring arms 24 and 25 which are firmly secured to the governor 16 at one end and carry rubbing contacts 26 and 27 at the free ends. lBetween the spring arms 24 and 25 is fastened an aluminum piece 2S which serves to keep the springs 24: and 25 in proper position. The governor as a whole is pivoted between two lugs 29 and 30 on the base plate 2 and firmly secured to the lug 30 is a brass cup 131 which incases one end of the governor 16 and its springs 2l and 25, thereby forming a brake or rubbing surface for the said springs 24 and 25. Now when the gear 15 rotates, the rotation is communicated to the governor 16 through the medium of the worm gear, and in rotating, the springs 24 and 25 are thrown out by centrifugal force, causing the part-s 26 and 27 to rub against the inside of the brass cup 3l to retard the movement. It will be seen therefore that as the speed of rotation increases, the parts 26 and 27 are made to bear more heavily against the brass cup, and vice versa. It will be seen -therefore that when it is desired to send a number of impulses through the medium of 'this device, the operator inserts a linger into a hole on thelinger hole dial v1 through which the vdesired number. appears and rotates said dial in a clock-wise direction until 'his finger meets the stop 32, at which time the nger is withdrawn. As before pointed out, the associated gears do not move during` this operation, but tension is stored in the spring 3, and the dog or ratchet spring 10 on spring 8 is rotated over a number of `teeth 7 inthe gear 6. New, however, when the linger is withdrawn the spring 3 exerts a force upon the dial 1,*causing said dial,

thereby causing the dial to come to a positive stop. As the dial returns to normal,

the dog 10 now catches in onel of the teeth 7 and thereby causes the gear 6 to rotate with the dial, the rotation of the gear 6 is communicated to the shaft 12 through the medium of pinion gear 11 and thereby rotates the cam wheel 17 .to cause the springs 18 and 19 to be separated momentarily a number of times. The speedV ofrotation of all the parts in returning to normal is made uniform by the coperation of the governor 16.

It will be seen that a device of this char- -acter is very efficientk but that owingto the strain placed upon certain gears and pivots, its life is made somewhat short. For instance I have found by observation that the gear wheel 15 which was heretofore made of steel, wears out very quickly on its Vteeth which coperate with the worm of governor 16. I have therefore made the gear Wheel 15 of a heavy piece of rawhide cut in the maimcr shown, which I have tested out and found to have a much longer life than such gears would have where a metal to metal surface was employed. I have also found that the governor wears out very quickly at other points due to the endwise pull exerted by the biased teeth of the gear 15, for instance, at the points where the rod 12 is pivoted, that is in the pivot screws or sockets 31 and 33, and also onthe rubbing surfaces ofthe parts 26 and 27.

In order to overcome this difliculty, I have provided jewel bearings for the shaft'16 at each end as shown in Fig. 11 at 34 and 35 which consist of a small piece of a hard stone set in the parts 31 and 33 and bearing against the ends of the shaft 16, and VI have also used avsinall part of rawhide for the outer or rubbing surfaces of the parts 26 a-nd 27. It will be seen therefore, that I have provided a very efficient and lasting method of constructing` a dial of this type, in which the parts upon which the greatest stress is exerted have no metal to metal rubbing surfaces and which type of impulse sender will ontlast by a considerable length of time those which are not iitted with such surfaces.

Having fully described the operation and method of construction of my invention, what I desire to secure and have protected by Letters Patent will be pointed out in the appended claims.

Ih at I claim as my invention is:

1. In an impulse transmitter having a governor, a source of power for operating ernor,said propeller being made of inher- `ently lubricating material for the purpose of preventing abrasion.

2. In an impulse transmitter in which a worin-gear is used in the operationof a.

governor, a gear-wheel for meshing with said worm-gear, said gear-Wheel being made 4c. In an impulse transmitter in which a of inherent@r lubricating material for the worm-gear is used in the operation of a govlo purpose of preventing1 abrasion between said ernor, a raw-hide gear-Wheel for meshing gears. with said worm-gear.

3. In an impulse transmitter having a Signed by me at Chicago, Cook county, governor, a Source of power for operating Illinois, this 17th day of December, 1917. y said governor, and a raw-hide propeller for ma governor. ALEXANDER E. KEITH.

Copies e! this patent may be obtained for ve cents each, by addressing ,thefcommilsloner of Patenti,

Washington, D. 0." 

